Implanon

Hey guys , so I got the birth control implanon about 2 weeks ago, and i had it Inserted a few days after my last period . My boyfriend and i decided to have unprotected sex last night , one of my friends told me I had to wait till I got my next period for it to be effective ? But the research I’ve been doing says you only have to wait 7 days after insertion to be protected . I’m not sure if I should go get plan b just to be safe or calm down since I may be protected . Please help!!